Vaccine With A Bit Of Cheek

2. May 2017

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Recommendations for vaccinations are ignored by many. Now bioengineers are trying to develop vaccines for domestic use, thereby eliminating the need to go to the doctor. Is it possible to overcome the skin mucosal barrier without a needle?

The current 2016/2017 influenza season is approaching its end. Greater efforts are needed to communicate the benefits of vaccination with more focus on the target groups, is one comment often heard. It was already shown years ago that this approach does not work. One alternative is to develop technological systems which can be employed by lay people without the need for them to turn to health professionals.

Nebulous nasal sprays

Nasal sprays play a major role here. In the US, patients have been putting their trust in FluMist for years. However its use is controversial. Before the start of the last flu season, experts from the Centers for Disease Control and Prevention (CDC) issued a comparatively clear warning. Attenuated intranasal live influenza vaccine have achieved no demonstrable effect in patients between two and 17 years of age, the agency writes. The basis for this was data from the US Influenza Vaccine Effectiveness Network. For only three percent of all study participants did protection take hold. As a comparison: injections by doctors of commercially available vaccines yielded a figure of 63 percent.

“If one sees no effect from a vaccination for three years in a row, should we really have to wait for more data and administer a vaccine that is probably no more effective than salt water?” asks Ruth Karron, Chairman of the CDC working group for flu vaccinations. Health authorities in other countries in actual fact do not share this view, although they see similar problems: How is it possible to better transport vaccines through the mucosal skin barrier without using a needle?

High pressure, big success

Dorian Liepmann from the University of California (UC), Berkeley, now foresees a needle-free system that patients could use themselves. MucoJet is a cylindrical15 millimetre long plastic capsule with a diameter of eight millimetres. It is made of inexpensive, biocompatible components derived by 3D printing and consists of several chambers.

The outer section contains sterile water. The inner part consists of two sections. One chamber is filled with the vaccine solution, and the other contains sodium bicarbonate and citric acid in solid form.

In order to vaccinate oneself, it is sufficient to lightly lay MucoJet onto the mucosa and to press on it externally with two fingers. By doing so, a membrane in its interior is broken. Water, hydrogen and acid come together to produce carbon dioxide as a blowing agent. If the pressure is strong enough, vaccine solution is ejected through a nozzle and passes through the mucous membrane into deeper layers. “The pressure of the jets is similar to the water jet which dentists use for cleaning”, says Kiana Aran, co-author of the study.

In the next step Liepmann developed a system in order to test the effectiveness of MucoJets. He worked with buccal tissue from pigs and applied ovalbumim. Droppers or oral sprays, some of which are used for influenza vaccination in the United States, served for comparison.

By way of the new route of administration, protein concentration at the target increased eight fold. “If the pressure is high and the diameter of the beam is very small, the substance goes easily through the mucous layer”, Aran says. Following initial pilot studies in animals, further investigation is required.

Going with nano into the body

Another strategy is being pursued by researchers at the “Platform for Efficient Epithelial Transport for Pharmaceutical Applications through Innovative Particulate Support Systems” (PeTrA). They managed to develop vaccine-loaded nanoparticles that land by means of a finely atomised fluid in the lungs.

They see a major advantage of the new method in that the vaccine finds its way into the body along the same path as many pathogens. As such our body can more easily form an effective immune response. Researchers have been successful both with mice models and in a test system with human cells. Their nano vaccine elicited the desired immune response. This works not only in our airways. Two years ago it was able to be proved that immunologically active molecules could be transported into the body via hair follicles.

Research takes time

The main commonality: all projects are currently still in their early experimental stages. Four or five years may come to pass before this technology acquires general use. Therefore quick solutions are needed – a situation calling for political action. Experiences in Switzerland show how this could work. The confederations have continually expanded their network of vaccination pharmacies. Low threshold services bridge the gap until patients have access to innovative solutions.